Despite the availability of several immunosuppressive treatments for autoimmune diseases, there remains a large unmet need for more efficacious and safer drugs in a large fraction of the patient population. For example, despite the reported efficacy of B cell depleting/inhibiting therapies like Rituximab and Belimumab in rheumatoid arthritis, systemic lupus erythematosus, Sjögren's syndrome, and multiple sclerosis, these therapies are only effective in a portion of diseased individuals, and with Rituximab, with an accompanying risk of progressive multifocal leukoencephalopathy. Further, multiple other leukocyte cell types are often involved in the pathology of these autoimmune diseases such as macrophages, dendritic cells and T cells, therefore therapeutic intervention targeting additional cell types or key immunological pathways that would inhibit their function could provide benefit. Given the multiple immunologically relevant roles of CD40-CD154 in the activation and function or these cell types, it is likely that an anti-CD40 antibody would confer therapeutic benefit to patients suffering autoimmune diseases outlined above beyond that currently provided by current therapies. Further, the central role for CD40-CD154 interactions in intestinal inflammatory disorders such as Crohn's disease and ulcerative colitis, and mechanistic links of the CD40 pathway to pathology in more rare disorders such as autoimmune vasculitis, pemphigus vulgaris, and idiopathic thrombocytopenic purpura (ITP) also highlights the potential of anti-CD40 antibodies in these indications.
The currently available immunosuppressants used after solid organ transplantation provide excellent short-term efficacy. Acute rejections within the de novo period are observed in 5%-20% of the recipients (depending on organ, patient population, and regimen) and the proportion of grafts lost to acute rejection within the de novo period is below 5% for any setting. Currently the key unmet need is the tolerability of immunosuppression with patient and graft survival in the long term. After renal transplant, 33% patients die and/or lose their graft within 5 years; the average age of death of transplant recipient is 58 years. Calcineurin inhibitors (CNI) remain the mainstay of immunosuppressive therapy for the vast majority of transplant patients. While nephrotoxicity and cardiovascular morbidity associated with CNIs is one of the drivers of chronic allograft nephropathy as well as patient death with a functioning graft, alternative primary immunosuppression have not been able to replace CNIs. Overall, there is still room for improvement in long-term transplant immunosuppression. B-cell mediated immunological damage of transplanted kidneys may contribute to poor long-term outcomes and the need for new agents to target B-cell rejection is increasingly recognised by the medical community.
Antibodies against CD40 are known in the art. Chir12.12 is a fully humanised, non-agonist anti-CD40 antibody (IgG1, kappa) that blocks CD154 (also known as CD40 ligand; CD40L)-mediated leukocyte activation and can mediate antibody-dependent cellular cytotoxicity (ADCC) of human leukocytes and B cell lymphomas in vitro (see WO 2006/073443). WO 2005/044306 describes anti-CD40 antagonist antibodies, including Chir12.12 for use in particular in the treatment of autoimmune and inflammatory disorders. Further Chir12.12 is effective in delaying kidney allograft rejection when dosed as a monotherapy in Macaca fascicularis (Cynomolgus monkeys) [Li et al. (2008) Transplantation; 86 (1):10-15]. However, Chir12.12 can also mediate depletion of peripheral B cells in non human primates (NHPs).
Anti-CD40 mAbs with silenced ADCC activity are predicted to have an improved safety profile relative to the parental anti-CD40 antibodies, and in particular may be more suitable for non-oncologic indications, such as autoimmune diseases and use in a transplant setting. The applicant has developed three silent anti-CD40 antibodies based on the Chir12.12 antibody. These antibodies, hereinafter designated mAb1, mAb2 and mAb3 are characterised by certain amino acid mutations in the Fc region which silence ADCC activity.
mAb1 comprises an N297A mutation in the antibody heavy chain amino acid sequence. The antibody comprises the heavy chain CDR1, CDR2 and CDR3 of SEQ ID NOs 3, 4 and 5 respectively, and light chain CDR1, CDR2 and CDR3 of SEQ ID NOs: 6, 7 and 8, respectively. mAb1 comprises a VH domain with the amino acid sequence of SEQ ID NO: 1 and a VL domain with the amino acid sequence of SEQ ID NO: 2. mAb1 comprises the full length heavy chain amino acid sequence of SEQ ID NO: 9 and the full length light chain amino acid sequence of SEQ ID NO: 10.
mAb2 comprises a D265A mutation in the antibody heavy chain amino acid sequence. The antibody comprises the heavy chain CDR1, CDR2 and CDR3 of SEQ ID NOs 3, 4 and 5 respectively, and light chain CDR1, CDR2 and CDR3 of SEQ ID NOs: 6, 7 and 8, respectively. mAb2 comprises a VH domain with the amino acid sequence of SEQ ID NO: 1 and a VL domain with the amino acid sequence of SEQ ID NO: 2. mAb2 comprises the full length heavy chain amino acid sequence of SEQ ID NO: 13 and the full length light chain amino acid sequence of SEQ ID NO: 14.
mAb3 comprises a L234A, L235A mutation (LALA) in the antibody heavy chain amino acid sequence. The antibody comprises the heavy chain CDR1, CDR2 and CDR3 of SEQ ID NOs 3, 4 and 5 respectively, and light chain CDR1, CDR2 and CDR3 of SEQ ID NOs: 6, 7 and 8, respectively. mAb3 comprises a VH domain with the amino acid sequence of SEQ ID NO: 1 and a VL domain with the amino acid sequence of SEQ ID NO: 2. mAb3 comprises the full length heavy chain amino acid sequence of SEQ ID NO: 17 and the full length light chain amino acid sequence of SEQ ID NO: 18.
Formulations with high concentration of antibody may have short shelf lives and the formulated antibodies may lose biological activity resulting from chemical and physical instabilities during the storage. Among those, aggregation, deamidation and oxidation are known to be the most common causes of antibody degradation. In particular, aggregation can potentially lead to increased immune response in patients, leading to safety concerns. Thus it must be minimised or prevented.
It is an object of the invention to provide further and improved formulations of anti-CD40 antibodies, and in particular formulations with high concentration of anti-CD40 antibodies and low levels of antibody aggregation.